aboutsummaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorLinus Torvalds <torvalds@linux-foundation.org>2009-08-27 12:26:02 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2009-08-27 12:26:02 -0700
commit9c504cadc443a3d002fa581ec5109c0ef02d7b14 (patch)
tree0b44c60843062e5ee8d91a636dab67ada5286156
parent4f8ee2c9cc0e885d2bb50ef26db66150ab25213e (diff)
parent0db501bd0610ee0c0aca84d927f90bcccd09e2bd (diff)
downloadlinux-stericsson-9c504cadc443a3d002fa581ec5109c0ef02d7b14.tar.gz
Merge branch 'for-linus' of git://git.infradead.org/users/eparis/notify
* 'for-linus' of git://git.infradead.org/users/eparis/notify: inotify: Ensure we alwasy write the terminating NULL. inotify: fix locking around inotify watching in the idr inotify: do not BUG on idr entries at inotify destruction inotify: seperate new watch creation updating existing watches
-rw-r--r--fs/notify/inotify/inotify_fsnotify.c33
-rw-r--r--fs/notify/inotify/inotify_user.c229
2 files changed, 177 insertions, 85 deletions
diff --git a/fs/notify/inotify/inotify_fsnotify.c b/fs/notify/inotify/inotify_fsnotify.c
index 5dcbafe72d71..c9ee67b442e1 100644
--- a/fs/notify/inotify/inotify_fsnotify.c
+++ b/fs/notify/inotify/inotify_fsnotify.c
@@ -105,16 +105,45 @@ static bool inotify_should_send_event(struct fsnotify_group *group, struct inode
return send;
}
+/*
+ * This is NEVER supposed to be called. Inotify marks should either have been
+ * removed from the idr when the watch was removed or in the
+ * fsnotify_destroy_mark_by_group() call when the inotify instance was being
+ * torn down. This is only called if the idr is about to be freed but there
+ * are still marks in it.
+ */
static int idr_callback(int id, void *p, void *data)
{
- BUG();
+ struct fsnotify_mark_entry *entry;
+ struct inotify_inode_mark_entry *ientry;
+ static bool warned = false;
+
+ if (warned)
+ return 0;
+
+ warned = false;
+ entry = p;
+ ientry = container_of(entry, struct inotify_inode_mark_entry, fsn_entry);
+
+ WARN(1, "inotify closing but id=%d for entry=%p in group=%p still in "
+ "idr. Probably leaking memory\n", id, p, data);
+
+ /*
+ * I'm taking the liberty of assuming that the mark in question is a
+ * valid address and I'm dereferencing it. This might help to figure
+ * out why we got here and the panic is no worse than the original
+ * BUG() that was here.
+ */
+ if (entry)
+ printk(KERN_WARNING "entry->group=%p inode=%p wd=%d\n",
+ entry->group, entry->inode, ientry->wd);
return 0;
}
static void inotify_free_group_priv(struct fsnotify_group *group)
{
/* ideally the idr is empty and we won't hit the BUG in teh callback */
- idr_for_each(&group->inotify_data.idr, idr_callback, NULL);
+ idr_for_each(&group->inotify_data.idr, idr_callback, group);
idr_remove_all(&group->inotify_data.idr);
idr_destroy(&group->inotify_data.idr);
}
diff --git a/fs/notify/inotify/inotify_user.c b/fs/notify/inotify/inotify_user.c
index dc32ed8323ba..0e781bc88d1e 100644
--- a/fs/notify/inotify/inotify_user.c
+++ b/fs/notify/inotify/inotify_user.c
@@ -47,9 +47,6 @@
static struct vfsmount *inotify_mnt __read_mostly;
-/* this just sits here and wastes global memory. used to just pad userspace messages with zeros */
-static struct inotify_event nul_inotify_event;
-
/* these are configurable via /proc/sys/fs/inotify/ */
static int inotify_max_user_instances __read_mostly;
static int inotify_max_queued_events __read_mostly;
@@ -199,8 +196,10 @@ static ssize_t copy_event_to_user(struct fsnotify_group *group,
inotify_free_event_priv(fsn_priv);
}
- /* round up event->name_len so it is a multiple of event_size */
- name_len = roundup(event->name_len, event_size);
+ /* round up event->name_len so it is a multiple of event_size
+ * plus an extra byte for the terminating '\0'.
+ */
+ name_len = roundup(event->name_len + 1, event_size);
inotify_event.len = name_len;
inotify_event.mask = inotify_mask_to_arg(event->mask);
@@ -224,8 +223,8 @@ static ssize_t copy_event_to_user(struct fsnotify_group *group,
return -EFAULT;
buf += event->name_len;
- /* fill userspace with 0's from nul_inotify_event */
- if (copy_to_user(buf, &nul_inotify_event, len_to_zero))
+ /* fill userspace with 0's */
+ if (clear_user(buf, len_to_zero))
return -EFAULT;
buf += len_to_zero;
event_size += name_len;
@@ -364,20 +363,53 @@ static int inotify_find_inode(const char __user *dirname, struct path *path, uns
return error;
}
+/*
+ * Remove the mark from the idr (if present) and drop the reference
+ * on the mark because it was in the idr.
+ */
static void inotify_remove_from_idr(struct fsnotify_group *group,
struct inotify_inode_mark_entry *ientry)
{
struct idr *idr;
+ struct fsnotify_mark_entry *entry;
+ struct inotify_inode_mark_entry *found_ientry;
+ int wd;
spin_lock(&group->inotify_data.idr_lock);
idr = &group->inotify_data.idr;
- idr_remove(idr, ientry->wd);
- spin_unlock(&group->inotify_data.idr_lock);
+ wd = ientry->wd;
+
+ if (wd == -1)
+ goto out;
+
+ entry = idr_find(&group->inotify_data.idr, wd);
+ if (unlikely(!entry))
+ goto out;
+
+ found_ientry = container_of(entry, struct inotify_inode_mark_entry, fsn_entry);
+ if (unlikely(found_ientry != ientry)) {
+ /* We found an entry in the idr with the right wd, but it's
+ * not the entry we were told to remove. eparis seriously
+ * fucked up somewhere. */
+ WARN_ON(1);
+ ientry->wd = -1;
+ goto out;
+ }
+
+ /* One ref for being in the idr, one ref held by the caller */
+ BUG_ON(atomic_read(&entry->refcnt) < 2);
+
+ idr_remove(idr, wd);
ientry->wd = -1;
+
+ /* removed from the idr, drop that ref */
+ fsnotify_put_mark(entry);
+out:
+ spin_unlock(&group->inotify_data.idr_lock);
}
+
/*
- * Send IN_IGNORED for this wd, remove this wd from the idr, and drop the
- * internal reference help on the mark because it is in the idr.
+ * Send IN_IGNORED for this wd, remove this wd from the idr.
*/
void inotify_ignored_and_remove_idr(struct fsnotify_mark_entry *entry,
struct fsnotify_group *group)
@@ -417,9 +449,6 @@ skip_send_ignore:
/* remove this entry from the idr */
inotify_remove_from_idr(group, ientry);
- /* removed from idr, drop that reference */
- fsnotify_put_mark(entry);
-
atomic_dec(&group->inotify_data.user->inotify_watches);
}
@@ -431,80 +460,29 @@ static void inotify_free_mark(struct fsnotify_mark_entry *entry)
kmem_cache_free(inotify_inode_mark_cachep, ientry);
}
-static int inotify_update_watch(struct fsnotify_group *group, struct inode *inode, u32 arg)
+static int inotify_update_existing_watch(struct fsnotify_group *group,
+ struct inode *inode,
+ u32 arg)
{
- struct fsnotify_mark_entry *entry = NULL;
+ struct fsnotify_mark_entry *entry;
struct inotify_inode_mark_entry *ientry;
- struct inotify_inode_mark_entry *tmp_ientry;
- int ret = 0;
- int add = (arg & IN_MASK_ADD);
- __u32 mask;
__u32 old_mask, new_mask;
+ __u32 mask;
+ int add = (arg & IN_MASK_ADD);
+ int ret;
/* don't allow invalid bits: we don't want flags set */
mask = inotify_arg_to_mask(arg);
if (unlikely(!mask))
return -EINVAL;
- tmp_ientry = kmem_cache_alloc(inotify_inode_mark_cachep, GFP_KERNEL);
- if (unlikely(!tmp_ientry))
- return -ENOMEM;
- /* we set the mask at the end after attaching it */
- fsnotify_init_mark(&tmp_ientry->fsn_entry, inotify_free_mark);
- tmp_ientry->wd = -1;
-
-find_entry:
spin_lock(&inode->i_lock);
entry = fsnotify_find_mark_entry(group, inode);
spin_unlock(&inode->i_lock);
- if (entry) {
- ientry = container_of(entry, struct inotify_inode_mark_entry, fsn_entry);
- } else {
- ret = -ENOSPC;
- if (atomic_read(&group->inotify_data.user->inotify_watches) >= inotify_max_user_watches)
- goto out_err;
-retry:
- ret = -ENOMEM;
- if (unlikely(!idr_pre_get(&group->inotify_data.idr, GFP_KERNEL)))
- goto out_err;
-
- spin_lock(&group->inotify_data.idr_lock);
- ret = idr_get_new_above(&group->inotify_data.idr, &tmp_ientry->fsn_entry,
- group->inotify_data.last_wd,
- &tmp_ientry->wd);
- spin_unlock(&group->inotify_data.idr_lock);
- if (ret) {
- if (ret == -EAGAIN)
- goto retry;
- goto out_err;
- }
-
- ret = fsnotify_add_mark(&tmp_ientry->fsn_entry, group, inode);
- if (ret) {
- inotify_remove_from_idr(group, tmp_ientry);
- if (ret == -EEXIST)
- goto find_entry;
- goto out_err;
- }
-
- /* tmp_ientry has been added to the inode, so we are all set up.
- * now we just need to make sure tmp_ientry doesn't get freed and
- * we need to set up entry and ientry so the generic code can
- * do its thing. */
- ientry = tmp_ientry;
- entry = &ientry->fsn_entry;
- tmp_ientry = NULL;
-
- atomic_inc(&group->inotify_data.user->inotify_watches);
-
- /* update the idr hint */
- group->inotify_data.last_wd = ientry->wd;
-
- /* we put the mark on the idr, take a reference */
- fsnotify_get_mark(entry);
- }
+ if (!entry)
+ return -ENOENT;
- ret = ientry->wd;
+ ientry = container_of(entry, struct inotify_inode_mark_entry, fsn_entry);
spin_lock(&entry->lock);
@@ -536,18 +514,103 @@ retry:
fsnotify_recalc_group_mask(group);
}
- /* this either matches fsnotify_find_mark_entry, or init_mark_entry
- * depending on which path we took... */
+ /* return the wd */
+ ret = ientry->wd;
+
+ /* match the get from fsnotify_find_mark_entry() */
fsnotify_put_mark(entry);
+ return ret;
+}
+
+static int inotify_new_watch(struct fsnotify_group *group,
+ struct inode *inode,
+ u32 arg)
+{
+ struct inotify_inode_mark_entry *tmp_ientry;
+ __u32 mask;
+ int ret;
+
+ /* don't allow invalid bits: we don't want flags set */
+ mask = inotify_arg_to_mask(arg);
+ if (unlikely(!mask))
+ return -EINVAL;
+
+ tmp_ientry = kmem_cache_alloc(inotify_inode_mark_cachep, GFP_KERNEL);
+ if (unlikely(!tmp_ientry))
+ return -ENOMEM;
+
+ fsnotify_init_mark(&tmp_ientry->fsn_entry, inotify_free_mark);
+ tmp_ientry->fsn_entry.mask = mask;
+ tmp_ientry->wd = -1;
+
+ ret = -ENOSPC;
+ if (atomic_read(&group->inotify_data.user->inotify_watches) >= inotify_max_user_watches)
+ goto out_err;
+retry:
+ ret = -ENOMEM;
+ if (unlikely(!idr_pre_get(&group->inotify_data.idr, GFP_KERNEL)))
+ goto out_err;
+
+ spin_lock(&group->inotify_data.idr_lock);
+ ret = idr_get_new_above(&group->inotify_data.idr, &tmp_ientry->fsn_entry,
+ group->inotify_data.last_wd,
+ &tmp_ientry->wd);
+ spin_unlock(&group->inotify_data.idr_lock);
+ if (ret) {
+ /* idr was out of memory allocate and try again */
+ if (ret == -EAGAIN)
+ goto retry;
+ goto out_err;
+ }
+
+ /* we put the mark on the idr, take a reference */
+ fsnotify_get_mark(&tmp_ientry->fsn_entry);
+
+ /* we are on the idr, now get on the inode */
+ ret = fsnotify_add_mark(&tmp_ientry->fsn_entry, group, inode);
+ if (ret) {
+ /* we failed to get on the inode, get off the idr */
+ inotify_remove_from_idr(group, tmp_ientry);
+ goto out_err;
+ }
+
+ /* update the idr hint, who cares about races, it's just a hint */
+ group->inotify_data.last_wd = tmp_ientry->wd;
+
+ /* increment the number of watches the user has */
+ atomic_inc(&group->inotify_data.user->inotify_watches);
+
+ /* return the watch descriptor for this new entry */
+ ret = tmp_ientry->wd;
+
+ /* match the ref from fsnotify_init_markentry() */
+ fsnotify_put_mark(&tmp_ientry->fsn_entry);
+
out_err:
- /* could be an error, could be that we found an existing mark */
- if (tmp_ientry) {
- /* on the idr but didn't make it on the inode */
- if (tmp_ientry->wd != -1)
- inotify_remove_from_idr(group, tmp_ientry);
+ if (ret < 0)
kmem_cache_free(inotify_inode_mark_cachep, tmp_ientry);
- }
+
+ return ret;
+}
+
+static int inotify_update_watch(struct fsnotify_group *group, struct inode *inode, u32 arg)
+{
+ int ret = 0;
+
+retry:
+ /* try to update and existing watch with the new arg */
+ ret = inotify_update_existing_watch(group, inode, arg);
+ /* no mark present, try to add a new one */
+ if (ret == -ENOENT)
+ ret = inotify_new_watch(group, inode, arg);
+ /*
+ * inotify_new_watch could race with another thread which did an
+ * inotify_new_watch between the update_existing and the add watch
+ * here, go back and try to update an existing mark again.
+ */
+ if (ret == -EEXIST)
+ goto retry;
return ret;
}